Abstract:
This experiment began in 1902 at a Cool Temperate site in Germany. The parent material of the soil is loess which was deposited during the Weischel ice age as a 120-150 cm thick layer over calcareous moraine material of high density from the Saale ice age. The original ecosystem at this site was a grassland. The land use previous to the experiment was arable land.

The measurements made (data available), frequency, and methodology are listed below:

a) Vegetation measurements made and frequency

Yield: Every year Total above-ground dry matter: Not regularly Total dry matter offtake: Every year Carbon content of offtake: Every year Nitrogen content of offtake: Every year Every year: P, K, Mg on 6 main treatments.

b) Soil sampling

Details of soil sampling method: Soil samples are taken with an auger from the 0-30 cm layer. Samples are taken from the margins of the plots (width of margin 3m at minimum depending on crop). Mixed sample from 20 cores. Air-dried, ground to <2 mm, mechanical device for subsampling. Soil is separated into layers. Details of measuring depths and soil layers: 0-30 cm every year. 30-60,60-100 cm not regularly. Deep sampling to a depth of 5 m in the last 3 years.

Nitrogen 15 measurements in vegetation: Every year since 1993 Total soil nitrogen 15 measurements: 2 or 3 times a year since 1993 depending on task Total soil mineral nitrogen 15 measurements: 2 or 3 times a year since 1993 Nitrate nitrogen 15 measurements: Twice a year since 1993 Ammonium nitrogen 15 measurements: Twice a year since 1993 Details of isotope measurements: Total soil N-15: Elemental analyzer-MS coupling (EA-MS). Nitrate & ammonium in soil: extraction with 1N KCl, distillation after BREMMER-KEENEY, N-15 determination of ammonium sulphat by EA-MS or emission spectrometer. N-15 in OM: hot water extraction. All measurements are taken on samples from the nil plots. On other variants only total soil N-15 measurements at irregular intervals.

DATA AVAILABLE IN ELECTRONIC FORMAT

Yield data available in electronic format from 1903 Total dry matter offtake data available in electronic format from 1903 Nitrogen content of offtake data available in electronic format from 1959 Data available in electronic format for rainfall from 1956 Data available in electronic format for air temperature from 1956 Data available in electronic format for net radiation from 1956 Data available in electronic format for relative humidity from 1956

Description:
This url links to the GCTE-SOMNET home page where additional project information and methodology can be obtained. This site is currently in a data sharing phase of the network where actual data will become available shortly, at different levels of accessibility. Please follow this link for more information.